Indexable cutting inserts used in milling cutters of the above-specified kind are often of a generally quadrangular shape and have two pairs of opposite peripheral and front cutting edges defining therebetween at least two indexable cutting corners. The cutting insert is mounted on a milling cutter so as to present an operative cutting corner associated with a peripheral cutting edge substantially co-directional with a longitudinal axis of the milling cutter and its adjacent front cutting edge substantially transverse thereto. When the cutting insert is mounted at a leading end of the milling cutter, for cutting operations of the kind specified above, with both peripheral and front cutting edges being operative, the insert needs to be provided with both axial and radial supports. To this end, insert receiving pockets formed at leading ends of milling cutters' bodies usually have an axially supporting side wall perpendicular to the pocket's base surface and substantially co-directional with the longitudinal axis of the milling cutter body, and a radially supporting side wall perpendicular to the pocket's base surface and extending radially with respect to the longitudinal axis. The axially and radially supporting walls of the insert receiving pocket meet at an innermost corner region thereof which is designed so as to receive therein an inoperative cutting corner of the cutting insert.
When a milling cutter of the above kind has an extended flute with a plurality of cutting inserts mounted therealong to form a continuous cutting line, such as for example in U.S. Pat. No. 5,083,887, the necessity to provide the cutting inserts, or at least the ones mounted at a leading end of the cutter, with the axially supporting wall, has a disadvantage in that this axially supporting wall hinders the development of chips formed by another cutting insert disposed adjacent this wall.
To avoid the use of an axially supporting wall in an insert receiving pocket designed for carrying cutting inserts mounted at a leading end of a milling cutter, the pocket is sometimes provided with a pin located adjacent an innermost corner of the pocket and protruding from the radially supporting side wall thereof. This pin is adapted to abut a radially innermost portion of the cutting insert's side surface associated with an inoperative front cutting edge thereof.
However, the above arrangement is not suitable for cases when cutting inserts of different geometries of cutting corners are to be mounted in the same insert receiving pocket. For example, a cutting insert having a cutting corner of relatively large radius cannot be supported by a pin designed to abut a cutting insert having a cutting corner of relatively small radius.
It is an object of the present invention to provide a new cutting insert and a new arrangement of its axial support in a milling cutter which, inter alia, have advantages in the above respect.